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The study of energy and its transformations as it pertains to living systems in the context of biochemistry.

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Could a mammal convert ingested dissolved CO2 to usable energy?

I'm trying to find out if it's possible that a mammal could orally ingest dissolved CO2 and convert it to energy for body heat, organ function, etc. Unfortunately, most of the scientific sources I've ...
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Are potential calories/ATP lost from fat when converted to ketones?

When insulin levels are low, the liver begins to oxidize fat. The liver oxidizes fat by an incomplete process that yields ketone bodies. The incomplete oxidation of fatty acids by the liver yields ...
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66 views

Recent research in bioluminescence powering photosynthesis?

In 2013 there was a Chinese study published on "Bioluminescence as a light source for photosynthesis," which is briefly summarized in this Chemistry World article. There was a question on Biology.SE ...
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18 views

Cell growth and lactic acid

I'm new on this forum so I apologize if I do anything wrong. I'm currently reading a book named Bioreaction engineering principles (3rd Ed.) to understand the more mathematical aspect in cell ...
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2answers
65 views

What is the primary energy source for sprouting plants?

To what extent are young plants powered by the potential energy stored in the seeds and when does solar energy take over? Are there other energy sources involved? I was observing sprouts in a ...
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1answer
154 views

Negative Oxygen Consumption Rate

Oxygen consumption rate (OCR) is defined as the rate at which cells consume oxygen. I reason that for cells not capable of photosynthesis, OCR is strictly non-negative. That was until I read this ...
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24 views

Muscle heat production during and after an effort

I noticed that I keep evacuating heat through sweat up to 15min after a running session, which gives me the impression that muscles keep producing heat even after the effort. It could be that muscle ...
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16 views

Energy transfer to reaction centre in higher plants

In a photosystem, the accessory pigment molecules in the LHC(light harvesting complex) absorb the quanta from different regions of PAR(photosynthetically active radiation) , their electron gets ...
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1answer
140 views

Can the Na+/K+ pump backwards to generate ATP?

The standard physiological direction of the Na+/K+ pump is to export 3 Na+, import 2 K+, and hydrolyze one ATP to ADP. Can it be driven backwards, importing 3 Na+, exporting 2 K+, and generating ATP? ...
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230 views

ATP stoichiometry of the Na+/K+ pump

The Na+/K+ ATPase pump exports 3 Na+ for every 2 Ka+ imported. This process is ATP dependent, but I have not been able to find how many ATPs are required in each translocation. What is the ...
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1answer
142 views

Does the energy from ATP hydrolysis vary among different cells?

I know that when ATP is hydrolyzed into ADP it gives 7.3 kcal/mol. The question is, does this value vary among different types of cells?
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181 views

Affinity for oxygen and carbon dioxide in animals

I'm currently reading Treatise on Invertebrate Paleontology (A) and don't understand the following fragment: The affinity for oxygen in lower animals is many times that in higher ones, whereas ...
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28 views

Bioenergetics of bioconversions: is there a surplus of energy?

By bioconversion, I mean a microbial process during which resting cells are used in order to convert a substrate to a desired product, whithout cell growth. For example, in this paper, they used ...
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271 views

Are there known life forms that are able to transform mechanical energy into chemical energy?

Are there known life forms that are able to transform mechanical energy into chemical energy? This question asks a similar subject, but more specific and has no answers. The background of this ...
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Measuring the Rate of Photosynthesis

Update: I have just received a grant to pursue this research. However, I must still perform the preliminary experiment described below before dipping into my very limited funds. Thank you for any ...
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30 views

Energy cost of chewing vs production of enzymes

Consider a hypothetical case that you ingest a piece of starch. Which is more costly energetically 1) chewing + reduced amount of enzymes production needed or 2) sole production of all the enzymes for ...
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0answers
49 views

Bioenergetics and equilibrium

"The living state is a non-equilibrium steady state to be able to perform work." I know that a "steady state" is the one in which the rate of energy gain is equal to rate of energy loss. Then how can ...
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1answer
168 views

How do plants store energy by potassium battery?

Plants have a so-called potassium battery system for energy storage/conversation. Wikipedia only has a reference to a technical article. Can someone explain it in a layman's language (or refer to a ...
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1answer
249 views

Is co-transport within a cell active or passive transport?

ATP is used to actively transport H+ out of the cell against the concentration gradient. The H+ & sucrose cotransporter, for example, then uses this proton gradient for transport. H+ goes back ...
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125 views

Organic battery?

Similar to the Matrix movie where humans were used as a source of electricity but different by using electric eels. Farmed like tuna what would be the electricity exchange to the food they eat?
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1answer
3k views

Location of t tubule in muscle

Why do mammalian skeletal muscles have t-tubules at the junction of the anisotropic and isotropic band, whereas non-mammalian muscles and cardiac muscles have it at Z-line? What could have been the ...
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2answers
848 views

What does “energy transfer in cells” mean?

"ADP and ATP are involved in energy transfer in cells." I know what is ATP and I know how ADP is formed, but I don’t understand what “energy transfer in cells” means.
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Can the NADPH/NADP+ ratio affect the FMN to FMNH2 ratio in the complex I of the mitochondria?

This is the reaction: FMNH2 + NAD(P)+ <-> FMN + NAD(P)H + H+ The reaction works either with NADH/NAD+ or NADPH/NADP+ I know that the NADH/NAD+ ratio affects the FMN to FMNH2 ratio But does the ...
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2answers
69 views

How did scientists establish the reactions that occur in metabolism? [closed]

How did scientists establish that macromolecules like proteins, carbohydrates and lipids are synthesized from other molecules with intermediate products by living cells. Did they observe this under ...
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3k views

Do all prokaryotes have ATP synthases and an electron transport chain?

I was looking this up and I'm wondering if so far I'm correct about the following: For the most part eukaryotes do aerobic respiration, which involves glycolysis, the Krebs cycle and oxidative ...
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Mechanism behind energy generation

I recently read about methanogens and methanotrophs. One converts CO2 to methane and vice versa respectively. I can't get exact mechanism for the methanotrophs and I know they can't be reversed ...
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1answer
327 views

How many calories do gut bacteria burn?

It has become well-accepted that microbiota of the gut (a.k.a. gut bacteria) consume calories that are ingested and can have significant effects on energy metabolism in humans. For example, if you ...
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1answer
77 views

Conversion of ATP to NADH without creating a proton motive force?

Is it possible to convert ATP into NADH and vice versa without first creating a proton motive force? If so by what mechanism is it done?
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335 views

In glycolysis, what is the source of the electron that makes NAD+ into NADH instead of NADH+? [closed]

I looked at the formula for the glycolysis reaction. The overall reaction seems balanced, however, I don't see anything on the left hand side of the equation that would provides the electron to ...
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2answers
150 views

What are the known energy capturing processes in biological systems?

I am not a biologist. I am aware that photosynthesis is the main process for capturing electromagnetic energy from the Sun. Also, I am aware that some bacteria can capture energy from boiling water ...
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46 views

What are the metabolic consequences of negative mechanical work in muscle contractions?

When a muscle contracts while it shortens (concentric), it consumes ATP I believe primarily due to cross-bridge shortening to remove the myosin head from it's attached state. However, when a muscle ...
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36 views

Is there any evidence to suggest that exercise reduces the side effects of caffeine?

I heard a friend say: I'm not drinking coffee this week. My body can only process the caffeine if I run at least 15km a week. I found this claim fascinating - that exercise temporarily increases ...
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1answer
11k views

Why do mice have a higher metabolic rate than humans?

Mice and other small animals have higher metabolic rate than humans. How does that happen on cellular level, if we look on one cell in the mouse body? What is it in this cell that will be different?...
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1answer
58 views

ATP yield of fermentation: study to cite?

Everywhere I find the ATP yields of respiratory and fermentative metabolism of glycolysis. While that of oxidative phosphorilation I could find in Stryer to cite one study where this was addressed (...
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1answer
188 views

Metabolic efficiency for fats and sugars

I am making an exercise for physics students about the first law of thermodynamics, burning heat and evaporation heat. So my idea is to use cycler which runs on fats and sugars where proportion ...
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1answer
2k views

Which step in endocytosis requires ATP?

Everybody seems to agree that endocytosis is an energy-using process, and as such requires ATP hydrolysis. However, which particular step requires it? More precisely, which 'molecular machine' ...
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2answers
2k views

Does ATP hydrolysis reaction have a high or low activation energy?

I was recently studying about ATP and how it functions as an energy carrier to all biological processes; however, I came across a confusing and paradoxical statement from two sources: (at 7:36) and (...
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128 views

Determining how much energy a plant takes in?

I asked a question on WorldBuilding.SE, "Are diamond berries possible?". This led to asking a question on Chemistry.SE about the amount of energy required to burn a 1 ct. diamond (−6.527kJ). The ...
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651 views

Energy transformations in chemiosmosis and ATP synthase

In terms of energy, how does chemiosmosis drive ATP synthase? How does electrical energy turn into mechanical energy and then into chemical energy? Would the movement of $H^+$ be considered passive ...
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263 views

Does the biosphere have infinite resources and are they infinitely renewable?

Does biomass represent all of the resources of the biosphere and therefore it would be theoretically infinitely renewable (as long as we have the sun) since all the biomass is part of the carbon cycle?...
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74 views

Cell energy consumption and food intake

I am wondering if each cell in human body starts consuming ten percent more energy, how much food one has to consume compared to normal intake?
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1answer
85 views

Energy consumption of a resting synapse

What is the energy penalty of maintaining rarely used synapse? I'm wondering if forgetting is cheaper than remembering unnecessary details.
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43 views

Beta oxidation of saturated fats

In my text book there is an example of a 18 carbon long fat and it says that it can run 8 laps of oxidation. I don't understand why it doesn't run 9? 2 are removed each cycle? Thanks.
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1answer
174 views

NADH shuttles - Why cytosol?

Why is the malate-aspartate and the glycerol-3-phosphate shuttles located in the cytosol and intermembrane space? The krebs cycle happens in the matrix so why wouldn't they push electrons from the ...
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1answer
481 views

Is there a significant difference in sedentary calorie-burn between a thinker and non-thinker?

I've read that, on average, a sedentary female burns between 1,600 - 2,000 calories and a sedentary male burns between 2,000 and 2,500 calories. I've also read that the brain itself burns quite a few ...
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1answer
167 views

Mitochondria variability per tissue in humans?

I would like to know the distribution of mitochondrial content per tissue type in humans. I understand the simple metric that energetically active or energy requiring tissues will have more ...
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1answer
669 views

What is the role of Aspartate Transaminase in gluconeogenesis?

I know that oxaloacetate cannot cross the mitochondrial membrane, but can instead be converted to aspartate, shuttled out, and then re-converted back to oxaloacetate. What does this have to do with ...
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3answers
2k views

Kinetic Vs Potential Energy in Biochemical Contexts

This question is causing great confusion in my head. Which of the following is an example of potential rather than kinetic energy? A) the muscle contractions of a person mowing grass B) water ...
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2answers
24k views

What causes muscles to generate heat on contraction?

I'm curious what the exact cause is of dramatic heat generation that comes along with muscle activity. Can anybody explain this in understandable language?
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What is the biological basis of “energy” that extraverted humans draw from social engagements and introverts expend?

This question is related to this question about introverts becoming exhausted after extended social events on cognitive sciences stack exchange. As I read more on the topic of human extraversion-...